crypto/openssh/compat.c

   1 /* $OpenBSD: compat.c,v 1.113 2018/08/13 02:41:05 djm Exp $ */
   2 /*
   3  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27
  28 #include <sys/types.h>
  29
  30 #include <stdlib.h>
  31 #include <string.h>
  32 #include <stdarg.h>
  33
  34 #include "xmalloc.h"
  35 #include "packet.h"
  36 #include "compat.h"
  37 #include "log.h"
  38 #include "match.h"
  39 #include "kex.h"
  40
  41 int datafellows = 0;
  42
  43 /* datafellows bug compatibility */
  44 u_int
  45 compat_datafellows(const char *version)
  46 {
  47         int i;
  48         static struct {
  49                 char    *pat;
  50                 int     bugs;
  51         } check[] = {
  52                 { "OpenSSH_2.*,"
  53                   "OpenSSH_3.0*,"
  54                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR|
  55                                         SSH_BUG_SIGTYPE},
  56                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE },
  57                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  58                                         SSH_BUG_SIGTYPE},
  59                 { "OpenSSH_2*,"
  60                   "OpenSSH_3*,"
  61                   "OpenSSH_4*",         SSH_BUG_SIGTYPE },
  62                 { "OpenSSH_5*",         SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT|
  63                                         SSH_BUG_SIGTYPE},
  64                 { "OpenSSH_6.6.1*",     SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
  65                 { "OpenSSH_6.5*,"
  66                   "OpenSSH_6.6*",       SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD|
  67                                         SSH_BUG_SIGTYPE},
  68                 { "OpenSSH_7.0*,"
  69                   "OpenSSH_7.1*,"
  70                   "OpenSSH_7.2*,"
  71                   "OpenSSH_7.3*,"
  72                   "OpenSSH_7.4*,"
  73                   "OpenSSH_7.5*,"
  74                   "OpenSSH_7.6*,"
  75                   "OpenSSH_7.7*",       SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
  76                 { "OpenSSH*",           SSH_NEW_OPENSSH },
  77                 { "*MindTerm*",         0 },
  78                 { "3.0.*",              SSH_BUG_DEBUG },
  79                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
  80                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
  81                 { "1.2.18*,"
  82                   "1.2.19*,"
  83                   "1.2.20*,"
  84                   "1.2.21*,"
  85                   "1.2.22*",            SSH_BUG_IGNOREMSG },
  86                 { "1.3.2*",             /* F-Secure */
  87                                         SSH_BUG_IGNOREMSG },
  88                 { "Cisco-1.*",          SSH_BUG_DHGEX_LARGE|
  89                                         SSH_BUG_HOSTKEYS },
  90                 { "*SSH Compatible Server*",                    /* Netscreen */
  91                                         SSH_BUG_PASSWORDPAD },
  92                 { "*OSU_0*,"
  93                   "OSU_1.0*,"
  94                   "OSU_1.1*,"
  95                   "OSU_1.2*,"
  96                   "OSU_1.3*,"
  97                   "OSU_1.4*,"
  98                   "OSU_1.5alpha1*,"
  99                   "OSU_1.5alpha2*,"
 100                   "OSU_1.5alpha3*",     SSH_BUG_PASSWORDPAD },
 101                 { "*SSH_Version_Mapper*",
 102                                         SSH_BUG_SCANNER },
 103                 { "PuTTY_Local:*,"      /* dev versions < Sep 2014 */
 104                   "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
 105                   "PuTTY_Release_0.5*," /* 0.58-0.59 */
 106                   "PuTTY_Release_0.60*,"
 107                   "PuTTY_Release_0.61*,"
 108                   "PuTTY_Release_0.62*,"
 109                   "PuTTY_Release_0.63*,"
 110                   "PuTTY_Release_0.64*",
 111                                         SSH_OLD_DHGEX },
 112                 { "FuTTY*",             SSH_OLD_DHGEX }, /* Putty Fork */
 113                 { "Probe-*",
 114                                         SSH_BUG_PROBE },
 115                 { "TeraTerm SSH*,"
 116                   "TTSSH/1.5.*,"
 117                   "TTSSH/2.1*,"
 118                   "TTSSH/2.2*,"
 119                   "TTSSH/2.3*,"
 120                   "TTSSH/2.4*,"
 121                   "TTSSH/2.5*,"
 122                   "TTSSH/2.6*,"
 123                   "TTSSH/2.70*,"
 124                   "TTSSH/2.71*,"
 125                   "TTSSH/2.72*",        SSH_BUG_HOSTKEYS },
 126                 { "WinSCP_release_4*,"
 127                   "WinSCP_release_5.0*,"
 128                   "WinSCP_release_5.1,"
 129                   "WinSCP_release_5.1.*,"
 130                   "WinSCP_release_5.5,"
 131                   "WinSCP_release_5.5.*,"
 132                   "WinSCP_release_5.6,"
 133                   "WinSCP_release_5.6.*,"
 134                   "WinSCP_release_5.7,"
 135                   "WinSCP_release_5.7.1,"
 136                   "WinSCP_release_5.7.2,"
 137                   "WinSCP_release_5.7.3,"
 138                   "WinSCP_release_5.7.4",
 139                                         SSH_OLD_DHGEX },
 140                 { "ConfD-*",
 141                                         SSH_BUG_UTF8TTYMODE },
 142                 { "Twisted_*",          0 },
 143                 { "Twisted*",           SSH_BUG_DEBUG },
 144                 { NULL,                 0 }
 145         };
 146
 147         /* process table, return first match */
 148         for (i = 0; check[i].pat; i++) {
 149                 if (match_pattern_list(version, check[i].pat, 0) == 1) {
 150                         debug("match: %s pat %s compat 0x%08x",
 151                             version, check[i].pat, check[i].bugs);
 152                         datafellows = check[i].bugs;    /* XXX for now */
 153                         return check[i].bugs;
 154                 }
 155         }
 156         debug("no match: %s", version);
 157         return 0;
 158 }
 159
 160 #define SEP     ","
 161 int
 162 proto_spec(const char *spec)
 163 {
 164         char *s, *p, *q;
 165         int ret = SSH_PROTO_UNKNOWN;
 166
 167         if (spec == NULL)
 168                 return ret;
 169         q = s = strdup(spec);
 170         if (s == NULL)
 171                 return ret;
 172         for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
 173                 switch (atoi(p)) {
 174                 case 2:
 175                         ret |= SSH_PROTO_2;
 176                         break;
 177                 default:
 178                         logit("ignoring bad proto spec: '%s'.", p);
 179                         break;
 180                 }
 181         }
 182         free(s);
 183         return ret;
 184 }
 185
 186 char *
 187 compat_cipher_proposal(char *cipher_prop)
 188 {
 189         if (!(datafellows & SSH_BUG_BIGENDIANAES))
 190                 return cipher_prop;
 191         debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
 192         if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL)
 193                 fatal("match_filter_blacklist failed");
 194         debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
 195         if (*cipher_prop == '\0')
 196                 fatal("No supported ciphers found");
 197         return cipher_prop;
 198 }
 199
 200 char *
 201 compat_pkalg_proposal(char *pkalg_prop)
 202 {
 203         if (!(datafellows & SSH_BUG_RSASIGMD5))
 204                 return pkalg_prop;
 205         debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
 206         if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL)
 207                 fatal("match_filter_blacklist failed");
 208         debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
 209         if (*pkalg_prop == '\0')
 210                 fatal("No supported PK algorithms found");
 211         return pkalg_prop;
 212 }
 213
 214 char *
 215 compat_kex_proposal(char *p)
 216 {
 217         if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
 218                 return p;
 219         debug2("%s: original KEX proposal: %s", __func__, p);
 220         if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
 221                 if ((p = match_filter_blacklist(p,
 222                     "curve25519-sha256@libssh.org")) == NULL)
 223                         fatal("match_filter_blacklist failed");
 224         if ((datafellows & SSH_OLD_DHGEX) != 0) {
 225                 if ((p = match_filter_blacklist(p,
 226                     "diffie-hellman-group-exchange-sha256,"
 227                     "diffie-hellman-group-exchange-sha1")) == NULL)
 228                         fatal("match_filter_blacklist failed");
 229         }
 230         debug2("%s: compat KEX proposal: %s", __func__, p);
 231         if (*p == '\0')
 232                 fatal("No supported key exchange algorithms found");
 233         return p;
 234 }
 235